Green tea is made from steamed and dried tea leaves that, unlike the leaves for black tea, have not been fermented. Its delicate flavor translates to a light, refreshing ice cream. After a day or two, the acids that occur naturally in the tea become more pronounced, so it is best to eat the ice cream soon after making it. Though convenient, tea bags do not make the best tea, as the leaves are not able to circulate. For better flavor, seek out high-quality loose tea sold in tea shops or specialty-food stores. Avoid common commercial brands, which are made from blends of inferior bits of leaves.